Not able to authenticate and connect to API - iOS

Hello. I’m planning to make an iPhone application for WordPress.org but I’ve encountered one problem. I’m not able to authenticate and connect to API, without the plug-in from a third party. Is there a way to do it without the plug-in?

hi , i always use third party plugins … I think there is no other simple way …
In my mind , there is no way except to use third party plugins.